CAUSES OF VARIATION IN PROPERTIES OF CASTINGS CONFORMING TO BS4844: 1986 GRADE 3D HIGH CHROMIUM WHITE CAST IRON

1 BHERO Shepherd
Co-authors:
2 MAVHUNGU Steven
Institutions:
1 Department of Chemical, Materials and Metallurgical Engineering, Botswana International University of Science and Technology
2 Metal Casting technology Station, University of Johannesburg, South Africa
Conference:
26th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, May 24th - 26th 2017
Proceedings:
Proceedings 26th International Conference on Metallurgy and Materials
Pages:
109-116
ISBN:
978-80-87294-79-6
ISSN:
2694-9296
Published:
9th January 2018
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
42 views / 15 downloads
Abstract

High chromium iron castings have been observed to exhibit significantly varying mechanical properties. To establish the origin of inconsistencies in properties, the research was conducted in two phases. First, monitoring to maintain consistency of charge materials and pouring temperature in order to eliminate extraneous operational variables from causative factors. Second, microstructural variations and consistency in mechanical properties were characterised and compared for different heats with small deviations in chemical compositions within the specification BS4844:1986 Grade 3D of high chromium white cast iron. The investigation revealed that marked inhomogeneity of microstructure as a result of variation in particularly chemical composition as well as operational parameters such as inconsistencies in pouring temperatures. The solution to this problem lies in narrowing the specification range by raising the lower limits to 2.5% C and 25% Cr, as well as controlling the pouring temperature to around 1550oC and reducing solidification time as much as possible.

Keywords: chromium iron, variation, mechanical properties
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